This invention relates to shelving systems consisting of vertical posts with slots and horizontal components with hooks going into these slots as shown in U.S. Pat. No. 4,063,835 by Husband, et al. Existing locking tabs integral with horizontal components as shown in Husband, et al and bent into post slots above the hooks of the horizontal components to prevent the latter from coming out of the post slots due to unusual or accidental side loads from earthquakes, collisions of forklifts against shelving etc., are unsatisfactory in two areas:
(1) It is very difficult and cumbersome to bend them back into their original position if the shelving has to be taken apart. PA1 (2) When the shelving is exposed to substantial shaking, they have a tendency to work loose. This is caused by the fact that the surface on the tab that locks against the top of the slot in the post is slanted forward after the tab is bent into its locking position. This combined with the upward movement of the hook and the sideways shifting when sideloads occur, will bend the locking tab back in small increments, but sufficiently fast to cause the horizontal components to come out after a few minutes of vigorous shaking. PA1 (1) Adding a secondary locking tab to the primary locking tab which allows to bend the whole tab back into its original position by inserting a screwdriver between the secondary tab and the post and twisting it. PA1 (2) Slanting the top surface of the primary tab backwards at an angle equal to or larger than the angle the tab is rotated forward when bent into the locking position, so that in the latter position the top surface of the primary tab is perpendicular to the centerline of the post or slightly slanted backwards.
To remedy these deficiencies it is possible to design more sophisticated locking devices, not integral with the horizontal shelving components, but these will increase erection time of the shelving and also make it more expensive.